Fort Fisher, built twenty miles south of Wilmington on the Cape Fear River at the start of the Civil War, was the largest and strongest earthwork fort in the world. As the Union blockade slowly closed all Southern ports, the fort was vital in keeping the river open to allow blockade runners to bring in supplies. Several times the Union tried top capture it and failed. On January 15, 1865, Fort Fisher finally fell to an overwhelming Northern force. Over 2,000 men were killed or wounded during the battle.